Ultrahigh Strength and Stiffness in Cross-Linked Hierarchical Carbon Nanotube Bundles

Electron irradiation induced covalent cross-linking at multiple length scales within double-walled nanotube bundles is demonstrated to lead to ultra-high effective strength and stiffness. In situ transmission electron microscopy tensile testing reveals order of magnitude enhancements in the mechanical properties as well as distinct failure mechanisms of cross-linked versus un-crosslinked bundles.